Alligator shears

ABSTRACT

An alligator shear for large scrap has a bed with widely spaced sets of horizontally disposed anvil blades. A wide jaw pivoted to the bed has shearing blades on opposite sides, which blades extend at a predetermined angle for part of the length of the knife beam and at a greater angle for the remainder of the length of the beam for coaction with the spaced sets of anvil blades on the bed to provide a double cut, there being fluid pressure operated cylinders pulling down on the jaw and there being a closed U-shaped guide for the front end of the jaw resisting thrust from either direction.

United States Patent 1 Swint, Jr.

[ 1 May8, 1973 [54] ALLIGATOR SHEARS [75] Inventor: Albert G. Swint, Jr., Cordelle, Ga.

[73] Assignee: Julius L. Chazen, Chattanooga,

Tenn.

[22] Filed: Mar. 15, 1971 [21] Appl.No.: 123,992

[52] US. Cl. ..83/599, 83/609, 83/694, 83/923 [51] Int. Cl. ..B26d 5/12 [58] Field of Search ..83/564, 599, 601, 83/605, 606, 607, 608, 609, 694, 923

[56] References Cited UNITED STATES PATENTS 363,524 5/1887 Libbey ..83/605 2,563,741 8/1951 Patton ..83/605 X 3,039,343 6/1962 Richards. ..83/694 X 3,387,523 6/1968 Pray ..83/609 X 1,320,923 11/1919 Richard... ..83/607 X 3,279,295 10/1966 Teplitz ..83/694 X 9/1942 Hoess ..83/599X 2/1972 Chazen ..83/609X FOREIGN PATENTS OR APPLICATIONS 467,752 10/1928 Germany ..83/609 7 Primary Examiner-Andrew R. .Iuhasz Assistant Examiner-James F. Coan Attorney-Morse & Morsell [57] ABSTRACT An alligator shear for large scrap has a bed with widely spaced sets of horizontally disposed anvil blades. A wide jaw pivoted to the bed has shearing blades on opposite sides, which blades extend at a predetermined angle for part of the length of the: knife beam and at a greater angle for the remainder of the length of the beam for coaction with the spaced sets of anvil blades on the bed to provide a double cut, there being fluid pressure operated cylinders pulling down on the jaw and there being a closed U-shaped guide for the front.

end of the jaw resisting thrust from either direction.

1 Claim, 4 Drawing Figures PATENTED 81973 3.731.577

INVENTOR ALBERT- G. SWINT, JR.

ATTORNEYS ALLIGATOR SHEARS BACKGROUND OF THE INVENTION movable cutting jaw co-acting with an anvil blade for action similar to that of a hand shear. The alligator type shear is advantageous over the guillotine type in that it is accessible from either side, whereas the guillotine type is usually accessible only from the front. Conventional alligator shears make only a single cut and usually have a back-up frame projecting upwardly from the bed at the rear of the shear blade for supporting the operating mechanism. This is expensive and cumbersome.

In pending application of Julius L. Chazen, Ser. No. 6,513, filed Jan. 28, 1970, an alligator shear is proposed which provides a double cut and wherein there is pull-down means in front of the jaw. The present invention contemplates improvements over the structure of the prior application in that the conventional rake angle of the upper knife, of the prior application, which extends in a straight line, while permitting progressive cutting of a given thickness starting at the jaw and moving outwardly toward the free end, decreases in value toward said outer end as the angle between the upper knife and the bed knife decreases to a low value. Thus shearing action at the outer end of the conventional shear with the straight knife provides progressively greater inefficiency and progressively less shearing capacity toward the outer end. Also in the prior Chazen application there is no means for bracing the movable beam against lateral thrusts, which becomes very necessary in a double cutting shear. Also in the prior application there is no way of preventing bulky scrap from escaping beyond the ends of the knives.

SUMMARY OF THE INVENTION The present invention provides an alligator shear having a bed with widely spaced sets of anvil blades and having a wide beam pivoted to the bed, with shearing blades on opposite sides. The beam has two knife portions at a dihedral angle with respect to one another for coaction with the spaced sets of anvil blades on the bed to provide a double cut. There is pull-down means in front of the beam connected between the forward end of the beam and the front end of the bed, and there is a confining guide for the front and both sides of the end of the beam effective to brace the beam against thrusts in either direction and to confine bulky scrap so that it cannot escape beyond the ends of the knives.

A general object of the invention is to provide an improved alligator shear in which the knives extend at one angle from the pivot point for a portion of the length of the beam, and at a different angle for the remainder of the length of the beam to provide for greater efficiency in the shearing of large scrap and to provide for relatively efficient shearing and greater shearing capacity throughout the length of the knives.

A further object of the invention is to provide an improved alligator shear having a novel confining guide for the free end of the beam to brace it against thrusts in either direction and to confine bulky scrap from endwise escape.

With the above and other objects in view, the invention consists of the improved alligator shear, and allof its parts and combinations, as set forth in the claims, and all equivalents thereof.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings, illustrating one complete embodiment of the preferred form of the invention, in which the same reference numerals designate the same parts in all of the views:

FIG. 1 is a side elevational view of the improved alligator shear, part of the hydraulic cylinder being broken away and part of the guide being broken out;

FIG. 2 is a fragmentary perspective view, looking principally at the end and side of the beam guide, showing the relationship of the end of the beam with the guide;

FIG. 3 is a section view taken approximately on the line 3-3 of FIG. 2; and

FIG. 4 is a fragmentary cross-sectional view through the anvil blades of the bed showing the shearing coaction of the jaw therewith.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring more particularly to the drawings, the numeral l0 designates a suitable bed having spaced side supports 11 and 12. Suitably supported on the rear portion of the bed to project upwardly therefrom are spaced pivot plates 13. The inner end of a movable knife beam 14 is pivotal on the axis of a pivot member The movable beam 14, instead of having a narrow shearing element as is common, has substantial width, as is clear from FIGS. 2 and 4. It has an underplate 16, the latter being T-shaped in cross-section to provide longitudinal grooves 17 as shown in FIG. 4. Removably secured to the plate in the grooves 17, by screws 18 are blades 19, the blades having outer sides 20 which are substantially flush with the corresponding sides of the underplate. 16. The lower longitudinal corners of the outer sides 20 constitute the shearing edges. When the blades become worn they can, of course, be removed and reversed to bring other corner edges in position for shearing action.

As a novel feature of the present invention, at least one extent of blades on the knife beam is in a plane at one angle with respect to the horizontal when the knife beam is in the raised position of FIG. 1, and at least one other extent of blades is in a plane at a greater angle with respect to horizontal, which latter extent is outwardly of the first extent. As a practical matter it works out well to have two extents of the blade at a dihedral angle with respect to one another. Accordingly, as a preferred means of carrying out this concept, the first two sets of blades on each side, which first two sets are designated 19a, extend for approximately two-fifths of the length of the beam at one angle with respect to the horizontal when the beam is up, and the last three sets of blades 19b extend for the last three-fifths of the length of the beam at a greater angle. The knives 19b 15, the latter extending between the spaced pivot plates are preferably at an angle of about 8 with respect to line (y) which is an extension of the plane of the lower surfaces of the blades 19a. Thus it may be said that the knives of the movable beam present a dihedral angle.

The shearing edges of the blades 19 are positioned to coact with the shearing edges 21 of anvil blades 22 (see FIG. 4). The latter are removably secured to the inner sides of spaced elongated anvil members 23 carried by the spaced side supports 1 l and 12 of the bed.

Projecting upwardly from the forward end of the bed are spaced guiding plates 24 which are braced against lateral thrusts by gusset plates 25 suitably secured to the plates 24 and to the top of the bed, there being a horizontal U-shaped plate 26 supported on the upper ends of the gussets 25. Supported on top of the U-shaped plate 26 is a beam guide housing 27 having a closed front 28 and sides 29. The sides 29 are an upward extension of the plates 24 and are in the same plane, but they angle rearwardly as shown in FIG. 1. They are braced by gusset plates 30. The latter are mounted on a U-shaped base portion 50 which is bolted to the top of the C-shaped plate 26 as shown. Extending downwardly at an angle from the upper ends of the side plates 29 and secured to the inner sides thereof, and also extending downwardly within the plates 24, are bearing strips 31 which are snugly slideably engaged by bearing blocks 32 on opposite sides of the front end of the beam as shown in FIGS. 1 and 2. The beam guiding housing 27 also provides a U-shaped protecting enclosure for the operating rod 33 which porjects from a fluid pressure operated cylinder 34. The latter is preferably a double acting hydraulic cylinder and has its upper end pivoted at 35 between plates 36 projecting from the forward ends of the spaced bed portions 11. The upper end of the piston rod is pivotally connected between spaced plates 37 at the forward end of the beam as at 38.

In operation, with the knife beam in the position of FIG. 1, scrap may be fed in from either side or may be fed from both sides simultaneously, the feeding being in the space between the beam guide housing 27 and the pivoted end of the beam. With the material in position, the hydraulic cylinder 34 is caused to operate in a pulldown direction to forcibly pull the beam down in a shearing stroke. During the start of such movement the knives 19a near the pivot act first, and inasmuch as these are at a substantial angle with respect to the anvil knives efficient shearing takes place. When the knife blades of the beam arrive at the broken line position (a) of FIG. 1 the knives 19a have completed their work. Due to the fact that the knives 19b are at a dihedral angle with respect to the knives 19a, a much improved shearing angle and greater capacity is maintained for the remainder of the stroke than would be true if all the knives extended in the same plane as the knives 19a which would be along line (b) of FIG. 1. Thus by changing the angle of the knives 19b there is greater shearing capacity at the outboard end of the knives as the greater angle produces more room between the knives 19b and the anvil blades 19. In addition there is a more efficient shearing stroke. When the beam completes its stroke the knives 19a and 19b will arrive at position (c).

During closing movement of the knife beam 14 the knife guide housing 29 provides an outboard guide for the beam 14, and due to the snug engagement of the wear blocks 32 with the wear strips 31 during shearing movement (as shown in FIG. 3) the beam is braced to resist thrusts from either side. This is very important because of the fact that scrap may be fed from either side of this double cutting shear.

To open the knife the hydraulic cylinder 34 is operated in a reverse direction. If a single out only is desired the material may be caused to project over only one set of the anvil blades 19. Normally, however, in order to obtain full use of the advantages of the present invention the material will be extended over the tops of both anvils, and when the beam 14 finishes its shearing stroke it will make a double cut to produce a cut piece having a suitable width for handling and storage. Also, as before mentioned, with the present invention material may be fed into the shear from either side, as the novel beam guide 27 braces the beam against thrusts from either direction.

With the improved arrangement of the present invention, the blades are engaged with the anvil on two sides during shearing, which also minimizes any effect from side stresses and always insures proper alignment of the movable blades. The arrangement also renders both sets of blades self-cleaning and, to a degree, selfsharpening.

It is to be understood that I do not desire to be limited to the exact details of construction shown and described, for obvious modifications will occur to a person skilled in the art.

What I claim is:

1. An alligator shear having an elongated bed with front and rear ends and provided with anvil blade means on one side and with laterally-spaced anvil blade means on the other side, a wide beam having front and rear ends and pivoted at its rear end to said bed'for pivotal movement to and from shearing position, said beam being of a width to fit between the spaced anvil blade means on the bed and having shearing blade means on one edge positioned to coact with the anvil blade means on one side of the bed and having shearing blade means on the other edge positioned to coact with the anvil blade means on the other side of the bed to provide a double cut, and said bed being exposed on both sides whereby material may be fed from either side of the shear, the improvement comprising a beam guide projecting angularly upwardly and inwardly from the front end of the bed, said guide having a front plate and having laterally-spaced side plates and being open toward the beam and being positioned to snugly slideably receive and confine the front end of the beam between said side plates and behind said front plate, a fluid pressure operated cylinder pivotally connected to the front of the bed forwardly of the anvil blades, and having an extensible rod positioned between the side plates of the beam guide and pivotally connected at its upper end to the beam at the forward end of the latter and within the confines of said beam guide, wear blocks on the forward end of the beam adjacent said pivotal connection, wear strips on the inner sides of the side plates of said beam guide, said plates and wear strips being so positioned with respect to the path of movement of the front end of the beam that the cylinder rod is confined throughout its movement and so that there is engagement between the wear blocks and the wear strips throughout the stroke of the shear, and means for laterally bracing said side plates whereby the beam guide resists thrust to either side, depending upon the direction of feed of the material into the shear. 

1. An alligator shear having an elongated bed with front and rear ends and provided with anvil blade means on one side and with laterally-spaced anvil blade means on the other side, a wide beam having front and rear ends and pivoted at its rear end to said bed for pivotal movement to and from shearing position, said beam being of a width to fit between the spaced anvil blade means on the bed and having shearing blade means on one edge positioned to coact with the anvil blade means on one side of the bed and having shearing blade means on the other edge positioned to coact with the anvil blade means on the other side of the bed to provide a double cut, and said bed being exposed on both sides whereby material may be fed from either side of the shear, the improvement comprising a beam guide projecting angularly upwardly and inwardly from the front end of the bed, said guide having a front plate and having laterally-spaced side plates and being open toward the beam and being positioned to snugly slideably receive and confine the front end of the beam between said side plates and behind said front plate, a fluid pressure operated cylinder pivotally connected to the front of the bed forwardly of the anvil blades, and having an extensible rod positioned between the side plates of the beam guide and pivotally connected at its upper end to the beam at the forward end of the latter and within the confines of said beam guide, wear blocks on the forward end of the beam adjacent said pivotal connection, wear strips on the inner sides of the side plates of said beam guide, said plates and wear strips being so positioned with respect to the path of movement of the front end of the beam that the cylinder rod is confined throughout its movement and so that there is engagement between the wear blocks and the wear strips throughout the stroke of the shear, and means for laterally bracing said side plates whereby the beam guide resists thrust to either side, depending upon the direction of feed of the material into the shear. 